1. Field of the Invention
The present invention relates to a compressor for, for example, a vehicle air-conditioner and, in particular, to a compressor having a suction muffler structure for damping a pressure pulsation in a coolant gas sucked from an external coolant circuit.
2. Description of the Related Art
A suction muffler structure of the above-mentioned type is disclosed, for example, in Japanese Unexamined Patent Publication (Kokai) No. 7-139463. That is, as shown in FIG. 6, a compressor is adapted to repeat a compression cycle comprising the suction of a coolant gas from a suction chamber 102 to a compression chamber 103, the compression of the sucked coolant gas and the discharge of the compressed coolant gas to a discharge chamber 104 by a reciprocation of a piston 101 in the horizontal directions as seen in the drawing. A muffler chamber 105 is formed between an external coolant circuit and the suction chamber 102. Accordingly, a pressure pulsation of the coolant gas sucked from the external coolant circuit into the compression chamber 103 is damped due to an expansion type muffler action of the muffler chamber 105, whereby the vibration or noise generated in a piping of the external coolant circuit due to this pressure pulsation can be reduced.
Generally, a vehicle air-conditioner has a compressor often disposed at the lowest position in a refrigeration circuit because the compressor is driven by a vehicle engine which is located at a lower position in a vehicle body. Therefore, the liquid coolant in the external coolant circuit is liable to flow into the compressor while the vehicle is stopped due to the height difference, and if the vehicle is stopped for a long time, the suction chamber 102, the muffler chamber 105 and the suction passage 106 are almost filled with the liquid coolant before the compressor is restarted.
In the suction muffler structure shown in FIG. 6, an inlet 107 of one of a plurality of suction passages 106 connecting the muffler chamber 105 to the suction chamber 102 opens at the lowermost position thereof. That is, the muffler chamber 105 has almost no volume in a region lower than the inlet 107 to the lowest suction passage 106. Accordingly, there is a problem that liquid compression continues for a long time because the liquid coolant in the muffler chamber 105 moves to the suction chamber 102 in a liquid phase, resulting in increase in vibration and noise caused by the liquid compression.
An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a compressor having a suction muffler structure which is capable of reducing generation of vibration and noise due to the liquid compression.
To achieve the above object, there is provided a compressor, according to the invention, comprising a housing having a compression chamber and a suction chamber defined adjacent to each other in the housing, a movable member associated with the compression chamber so that a coolant gas is sucked from the suction chamber into the compression chamber, compressed in the compression chamber and discharged from the compression chamber, and a suction muffler structure. The suction muffler structure comprises a muffler chamber provided between the suction chamber and an external coolant circuit, a suction passage connecting the muffler chamber to the suction chamber, the suction passage having an inlet from the muffler chamber, and the muffler chamber having a liquid-storage space formed in a region in the muffler chamber lower than the inlet.
According to the invention as described above, the liquid coolant flowing, for example, from the external coolant circuit into the muffler chamber is temporarily stored in the liquid-storage space. Since the inlet to the suction passage is provided at a position above the liquid-storage space, the liquid coolant in the liquid-storage space hardly moves to the suction chamber via the suction passage while in a liquid phase. The liquid coolant in the liquid-storage space is evaporated by the heat generation of the compressor during the operation thereof and finally moves to the suction chamber in a gas phase. Accordingly, it is possible to reduce generation of vibration and noise accompanied with the liquid compression.
Preferably, the muffler chamber is formed by a muffler housing attached to the housing of the compressor and a muffler cover fixedly secured to the muffler housing at a parting line so as to extend partly in the muffler housing and partly in the muffler cover, the suction passage being formed in one of the muffler housing and the muffler cover to extend to the muffler chamber, the inlet being disposed at a position not exceeding the parting line between the muffler housing and the muffler cover.
In this feature, the structure forming the inlet of the muffler chamber to the suction path is disposed at a position not exceeding the abutment line between the muffler housing and the muffler cover. Therefore, a grinding operation is not disturbed by the structure forming the inlet, whereby it is possible to prevent the workability from deteriorating when a surface of the muffler housing or the muffler cover to be in contact with the corresponding surface of the other is ground.
Preferably, the inlet from the muffler chamber to the suction passage opens upward or downward.
For example, if the inlet of the muffler chamber to the suction path opens laterally, there might be a height difference in the inlet corresponding to a diameter thereof. Therefore, a volume for a liquid-storage space would be reduced. Contrarily, according to the invention defined by claim 3, the inlet to the suction path opens either upward or downward in the muffler chamber. Therefore, there is no height difference in the inlet to ensure the liquid-storage space of a larger volume.
Preferably, the muffler housing has an outer wall to partly form the muffler chamber and a tubular wall in the outer wall to form the suction passage.